Retention system for electrical contacts



Jan. 12, 1965 J. W. MASTON RETENTION SYSTEM FOR- ELECTRICAL CON'IIACTS Filed Aug. 13, 1962 United States Patent *AO 3,l65,369 'RETEN'HN SYSTEM FR ELECTRHCAL CONACTS .llames W. Maston, Altadena, Caliit., assigner, by mesne assignments, to international Telephone and ieiegraph Corporation, New York, Nik, a corporation E Marylmd Filed Aug. 13, i962, Ser. No. 216,445 13 Claims. (El. 339-59) The present invention relates to electrical connectors of the type having a plurality of contacts in one connector member which are matable with a plurality of contacts in another connector member when the members are interengaged, and the invention relates particularly to novel snap-in retention means in the connector members for ermitting the contacts to be snapped into their operative positions in respective bores in the insulators of the connector members, and also permitting the contacts to be released for withdrawal from the respective bores by use of a suitable release tool.

Various systems have been employed in the electrical connector art for snap-in retention of the contacts in the insulation bodies of the connector members. Most systems of this general type utilize individual spring retention clips or rings which circumscribe the respective contact members and are either mounted on the contacts for engagement against respective shoulders in the insulator bores or are mounted in the bores for engagement against respective shoulders on the contacts. The use of such separate contact retention clips or rings for each of the Contact members presents a relatively dirlicult assembly problem, being both time consuming and costly, particularly where a large number of contacts are employed, and where thecontacts are small and closely spaced, as in the miniature, sub-miniature and micro-miniature types of connectors.

With the use ot individual contact retention clips or rings, it is ditlicult to provide uniform retention characteristics for all of the contacts, and this again is particularly true in small connectors, where the clips or rings are too small to be predictable or reliable for providing positive contact retention.

A further problem o particular importance in very small connectors is that size limitations seriously limit the amount of space available for contact retention structures, and because of this it is very difficult to provide retention devices having adequate strength for positive Contact retention, yet which can be readily deilected for entry and removal of the contact members.

lt is desirable in connection with releasable snap-in contact retention devices to have the contacts insertable into the insulator bores from the rear and rearwardly removable from the bores by the use of a rear entry tool. However, this is a diihcult arrangement to provide in connectors having a dense array of small contacts with conventional retention structures, because of space limitations and of the generally fragile nature of the retention members.

in view of these and other problems in the art, it is an object of the present invention to provide a novel snap-in Contact retention system for an electrical connector wherein a unitary wafer or web in the connector member has a plurality of resilient Contact retention structures formed thereon, whereby a plurality of Contact members are releasably retained in the connector member Without requiring separate retention devices for the individual contacts.

Another object of the present invention is to provide a contact retention system ofthe general character described for an electrical connector wherein a plurality of resil-.

iently deformable contact retention cones are integrally Hee formed on a unitary wafer or web having bores therethrough axially aligned with the respective cones, the cones being axially slit and resiliently deformable so that they are readily expansible for contact insertion into and removal from the bores, the cones resiliently closing behind shoulders on the respective contacts upon insertion of the contacts to provide retention structures in the form of substantially closed sleeves having high column compressive strength characteristics in an axial direction for positive axial retention of the contacts.

A further object of the invention is to provide a contact retention wafer or web of the foregoing character which may be disposed against the rear face of the connector insulation body having contact-receiving bores therein which are in alignment with the bores of the web or wafer, so that each of a plurality of Contact members can be inserted through a bore of the Wafer into the aligned insulator bore to be supported in the insulator and axially retained against rearward movement by a respective retention cone of the wafer, and the terminal may be released for rearward withdrawal by deilecting the cone with a suitable rear entry tool.

An additional object of the invention is to provide a novel snap-in contact retention structure of the character described which may be formed as a single molded plastic unit which serves as a part of the insulator structure of the connector member, and which is suitable for positive retention of a large number of closely spaced contact terminal members.

Further objects and advantages of the present invention will appear during the course of the following part of the speciiication wherein the details of construction and mode of operation of a preferred embodiment are described with reference to the accompanying drawing, in which:

FIG. l is a fragmentary vertical section, with portions in elevation, illustrating an electrical connectorrmember embodying the present snap-in contact retention system, with one contact member illustrated in a partially inserted position but before its respective contact retention cone has been deflected.

FIG. 2 is a fragmentary vertical section, partly in ele- Vation, illustrating a part of the structure shown in FIG. l, but with the contact member further inserted to a point at which a retention collar on the contact has deilected and circumferentially expanded the cone.

FIG. 3 is a view similar to FIG. 2, but with two contacts inserted to their forwardmost position in the bores, the collars on the Contact members having moved forwardly past the forward edges of the cones and the cones having resiliently closed behind the collars to provide positive retention of the terminals against rearward Withdrawal from the connector member.

FIG. 4 is a vertical section, partly in elevation, illustrating the connector member of FIGS. l-3 operatively engaged with another connector member employing a similar Contact retention system, the opposing contact lterminal members being in their fully inserted positions in Ithe two` connector members and being mated with each ot er.

FIG. 5 is a transverse sectional view along the line 5-5 in FIG. 4.

Referring to the drawings, FIG. 1 illustrates an electrical connector member l0 which includes an insulation body l2 having a front face 14 and a rear face 15, with a plurality of parallel contact terminal-receiving bores 16 extending therethrough between the faces 14 and 15. The outer peripheral structure of the connector member lil has not been illustrated, as it may be of any conventional form. For example, the insulation body l2 may be mounted in a rigid tubular outer shell if desired, or the insulation body 12 may itself form the Veach-of which is 180? in extent.

outer structure of the connector member without requiring the addition of a separate outershell.

Each of the bores i6 includes a generally cylindrical contact mounting section 13 which provides lateral stabilization for the contact member that is supported therein, and also includes an enlarged rearward bore portion 2t) which extends from a rearwardly facing shoulder 22 in thev bore to the rear face 15 of the insulation body. Y

The insulation body l2 is adapted to support socket y contact terminals therein, and accordingly the bores 16 Vare each provided with a constricted forward bore section 24 having a chamfered entrance ramp 26 leading to the front insulator face 14, for guiding a pin contact terminal ofanother connector member into mating engagement with the socket contact terminal mounted in the bore 16.

Disposed against Vthe Vrear face Vl of insulation body l2 in a contact retention wafer or web 28 having a front face Sil which is flush against the rear insulation body face 15, andV having a rear face 32. Passages 3d extend through the wafer 2d in axial alignment with the int sulator bores lo, so that when a Contact terminal is to be wardly, having Van inner frusto-conical surface 38 andY an outer truste-conical surface di), the cone terminating at a forward edge 42. The tapered inner surface 38 AThe passage 34 may have a frusto-conical surface as shown in the drawing, or alternatively the passage` 3d may extend yrearwardly from the cone 36 in a generally cylindrical conguration, with theA entrance flare being provided in the form of a chamfer or bevel at the rear i endof the passage 34.

The forward edge 42 of each contact retention cone 3o is axially oifset to the rear of the rearwardly facing bore shoulder V22 so that a retention collar on the Contact member will be positioned between the forward cone Vedge i2 andthe rearwardlyfacing shoulder 22 when the terminal is operatively positioned in the bore, as will be described in detail hereinafter.

The cones are each provided with one or more axially arranged slits d4 which extend from the forward vedge 42 of each cone to the base'of the cone proximate the front face 30 of wafer 28. As best shown in FG. 5, the embodiment of the invention illustrated in the drawings has two'diametrically disposed axial slits 4d in each of the cones 36, so as to divide the cone into two segments In the positions of repose of the cones 26, as shown in FIGS. 1, 3, 4 and 5, the

.cones are radially constricted so that the slits 44 are sub- However, because of the slits 44, andV The axial slits 4d are provided in the cones dby movement of a sharp cutting tool axially relative to the cones. This slitting, procedure is quite simple, Vand results in slits which are virtually closedV in thepositions of repose of the cones, as desired. Cutting or molding slots in the cones would Vbe extremely difficult, and would result in spacingtthe cones sections apart, whic'nis undesirable,

particularly in the caseof small connectors, as it weakens the cones. r

The contact retention wafer 218,y including thecones 36, is preferably molded yas an integral unit of a tough plastic material which, when Vmade in relatively thin-walled form, is resiliently deformable, With sucha material, the relatively thick body portion of the wafer .2li will comprise a substantially rigid structure, whiiev the relatively thin-walled contact retention corresV 36 will have the Vdesired resiliently flexible or deformableV characteristics. Materials which have been found ,inv practice to be particularly suitable for the wafer 23, butr'whicrh are set forth herein by way of example only Vand not by way of limitation, are va polyamide suchV as"nylon,V a fluoroethylene such as Kel-F, an acetate such as ielrinj or a polycarbonate such as Lexan Such Vmaterials have excellent electrical insulation characteristics, 'and serve to increase the dielectric separation between adjacent contacts, which is' an important factor in permitting a dense,

closely spaced array of contact membersin small conf nectors, and this is an advantage of the present invention over the usual practice of providing metallic retention clips or rings for snap-incontact retention.

The wafer 28 may be secured in its operative position against the Vrear face l5 of insulation body 12 by any suitable means. For example, wafer Zti'may lie-bonded to the `rearrface of the insulation body i2 by a suitable cement, if desired. Another means for securing the wafer 2S in position relative to insulation body l2 is to supportv both'the body and the wafer28 in a common outer shell of the connector memben Another example of a means for retaining the wafer 28 in position would be to employ suitable fasteners between wafer 23 and insulation body l2, such as bolts or the like.

The socket contact member 46 which is adapted to be supported in one of the insulator bores lo and retained by the respective retention cone 36 may be of generally conventional form, and includes a forward mounting s section 48 ofv generally cylindrical conliguration adapted to be received and supported within the contact mounting section 18 of bore 16. YThe forward part of the mounting section 48 of contact member 45 comprises a tubular socket contacting portion Sd adapted to receive a mating pin contact member therein. The contact member 46 also includes a tubular rear portion S2 within'vwhich the bared end of a wire conductor 5d is soldered or crimped. The contact member 46 also'includes an annular collar 56 which serves asvth'e axial positioning structure on the contact member that is'engaged within the bore to limit both forward and rearward movement of the contact member. Thus, in the fully inserted position on the contact member 46 within bore 16, the forward shoulder Y 57 of collar S6 is invabutti'ng relationship with the rearwardly facing shoulder 22 in the'bore to limit forward movement of the contact member '45' inthe bore, while the rearward shoulder S3 of collar 56 is in abutting relationship with the forward edge 42 of the respective contact retention cone 36 to limit rearward movement of the contact member lid inthe bore.

FIGS. 1, 2 and 3 illustrate progressive stages in the insertion of contact memberV V46 Vin the bore V16. In FiG. 1, thefor-ward mounting section 4% of the contact member 46 has been inserted through the passage 34 in 'wafer 28 and through the retentionvcone 36, and is partly inserted into the mounting section lof the bore, butk the annular collar 56 on the ,contactmember has not as yet been inserted into the wafer passage 34. In

FIG. 2, the annular collar 56 has been inserted throughV nfl H 8 the wafer passage 34 and has radially spread the retention cone 36 to permit passage of the collar 56 therethrough. It will be noted that the gradual forward and inward taper of the cone 36 provides 4an excellent cam surface againstwhich the collar 56 works, and this coupled with the slits 44 and the resiliently deformable v nature of the cone 36 permits the collar 56 to be pushed through the cone with a minimum of forward force. It is also to be noted that the enlarged rearward bore section 2t) is sufficiently 4large in diameter to accommodate both the diameter of the collar 56 and the wall thickness of the cone 36 as the collar 56 is passing forwardly through the cone 36.

In FIG. 3, Athe collar 56 has passed forwardly beyond the forward edge 42 of cone 36, and the cone 36 has sprung back inwardly to its closed position of repose, in which the cone 36 presents a substantially closed, rigid tubular structure having relatively great column compressive strength to resist rearward axial movement of the contact member 46, so as to securely lock the contact member 46 in its operative position.

It will lbe `apparent `from FIG. 3 that release and removal of the contact terminal 46 may be simply effected by merely inserting a suitable tool from the rear into the clearance formed between the rear portion 52 of the contact and the wall of the wafer passage 34, so as to dellect the contact retention cone 36 outwardly beyond the collar S6, thus clearing a path for rearward withdrawal of the contact member out of the bore. One type of tool which is useful for this purpose is a tubular plastic tool which may be slidably engaged over the wire 54 and then over the rear portion 52 of the contact member 46. Such a resilient plastic t-ool may be axially slitted so that it can be circumferentially spread and engaged over the wire 54 without requiring that the wire be disconnected or cut. Such a tubular tool has the advantage of substantially full-circle engagement of the cone 36 when the tool is pushed forwardly to are the cone outwardly beyond the lcollar 56.

However, where very small contacts are employed, as in micro-miniature connectors, the access space is so small that it is sometimes not practical to employ such a slitted, flexible tubular plastic tool, and a channelshaped metal tool blade or tongue must be used. Such a channel-shaped metal tool blade or tongue has a generally U-shaped cross-section, and in the case where a pair of the slits 44 are diametrically disposed in the cone 36, it is desirable to have this channel-shaped tool blade slightly convergent at the edges of the channel, so that the channel curves through more than 180, and will therefore effectively flare both of the 180 half-sections of the cone radially outwardly regardless of rotational orientation between the tool and the sections of the cone.

In FIG. 4 of the drawing a connector member 60 is illustrated in engaged relationship with the connector member 10, the connector member 6i) including an insulation body 61 having -a front face-62 and a rear face 64, with a plurality of bores 66 extending through the body 61 between faces 62 and 64. Each of the bores 66 has a forward contact mounting section 68 and an enlarged rearward bore section 70 which extends from a rearwardly facing shoulder 72 in the bore to the rear face 64 of the insulation body 61. The enlarged rearward bore section 70 has the same diameter and axial extent as the rearward bore section of insulation body 12. A contact retention wafer 28 identical to that shown in FIGS. l, 2 and 3 is supported against the rear face 64 of insulation body 61 so that each of the contact retention cones 36 extends into the enlarged rearward section 70 of the respective bore 66.

The insulation body 61 is adapted to support pin contact members 74 in the respective bores 66, each of the pin contact members 74 including a forward pin contacting portion 76 which is supported in the contact mounting section 68 of the bore and projects forwardly pin contact member 74 includes a tubular rear portion 78 for receiving the bared end of a wire conductor 80 which is soldered or crimped therein, and between the forward pin portion 76 and the tubular rear portion 78 is an annular collar 82 having the same diameter as the collar 56 on the socket contact member 46,

The pin contact member 74 is inserted into its respective bore from the rear and is rearwardly removable therefrom in the same manner as the socket contact member 46, and in the operative position of the pin contact member 74 the forward shoulder of collar 32 is in abutting relationship with the rearwardly facing shoulder 72 in the bore to limit forward movement of the contact member, and the rear shoulder of collar S2 is in abutting relationship with the forward edge 42 of the contact retention cone 36 forming a part of Wafer 28.

Although the present invention has been illustrated and described in connection with electrical connector members embodying socket and pin contact members, it is to be understood that the present contact retention system is equally adaptable for use in connection with any other types of mating contacts.

While the instant invention has been shown and described herein, in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein, but is to be accorded the full scope of the claims.

I claim:

1. An electrical connector unit comprising a body of insulation material having a plurality of passages therethrough from a front face to a rear face and adapted to receive respective electrical contact members therein which are insertable from the rear and which each have an enlarged section defining a rearwardly facing shoulder and a plurality of truncated, tubular contact retention cones integral with said bfody and coaxial with the respective said passages, each of said cones tapering forwardly and radially inwardly from the wall of the respective passage to a forward free end, each cone being resiliently radially expandable to permit said enlarged section of a respective contact member to pass therethrough upon forward insertion of the contact member into the respective said passage, the cone contracting behind the shoulder on the contact member to limit rearward movement of the contact member in the passage, and each cone being substantially rigid in an axial direction when in its contracted position so as to provide a positive stop against rearward movement of the respective contact member.

2. An electrical connector unit as defined in claim l, wherein said cones extend forwardly from said rear face of the body in axial alignment with the respective said passages.

3. An electrical connector unit as defined in claim 2, wherein the inner wall `of each cone forms a continuation of the wall of the respective passage.

4. An electrical connector unit as defined in claim 3 wherein each of said passages flares outwardly proximate said rear face of the body to provide an entrance ramp for insertion of the contaot member into the passage from the rear.

5. An electrical connector unit as defined in claim l, wherein the wall `of each cone has an axial slit therein, said slit being substantially closed in the position of repose of the cone and being adapted to open during the resilient radial expansion of the cone.

6. An electrical connector unit as defined in claim 5, wherein each cone has a pair of said axial slits substantially diametrically disposed therein.

7. An electrical connector unit comprising an insulator member having a bore therethrough from a forward face to a rearward face, said bore having an enlarged rearward section opening at said rearward face, rearwardly directed stop means in said bore, a wafer mounted against said rearward face of the insulator member and having a passage therethrough axially alig ed with said bore, said bore and passage being adapted to receive an electrical'contact member therein which is insertable from the rear and which has a forwardly facing shoulder thereon engageable with said stop means to'limit forward movement of the Contact member and has an enlargedsection delining v a rearwardly facing shoulder, and a truncated, tubular Contact retention cone integral with said wafer and coaxial with said passage, said cone tapering forwardly and radi-1 ally inwardly from the wafer to a forward freeend andV extending into said enlarged rearward bore section, said cone being resiliently radially expandable to permit said enlargedcontact section to pass therethrough upon for- Wardrinsertion of the contact member into the passage Y and bore, .the cone contracting behind said rearwardly facing shoulder on the contact member to limit rearward g movement of the contact member in the passage and bore,

- of insulation material mounted with a front face thereof against said rearward face of the insulator member and having a plurality of passages therethrough axially aligned with the respectiveV bores, an electrical Contact member mounted in each bore and the respective passage, said contact members being adapted for insertion from the rear and each having a forwardly facing shoulder thereon in abutting relationship-with said stop means to Y limit forward movement of the contact. member and each having an enlarged section defining a rearwardly facing shoulder, and a plurality of truncated, tubular contact retention cones integral with said wafer and coaxial with Y the respective said passages, said cones each tapering forradially expandable to permit said enlarged section of thev respective contact member to pass therethrough upon forward insertion of the contact member into the passage and bore, the cone contracting-behind said rearwardly facing shoulder on the contact member to limitV rearward movement ofthe contact member-in the passage and bore, and each-cone being substantially rigid injan axial direc.- tion when Vin its contracted position so as to provide a positive stop against,rearwardimovenient of the respective contact memben n Y 10. An electrical connector unit as defined lin claim 9, wherein the inner wallfof each cone forms ya continuation of the wall of the respective passage.

11.` An electrical Vconnectorunitas deiined in claim 9,

wherein the wall ofA each conchas an axial slit therein, said slit being substantially closed in the .position of repose of Vsaid cone and beingk adapted to open during the resilient radial expansion of the cone.

l2. An electrical connector unit as defined in claim 1l, wherein each cone has a pair of said axial slitss'ubstantially diametrically disposed therein. I

13.v An electrical connector unit as defined in claim l1, wherein said slitin the wall of each cone extends from said free end ofthe conerearwardly substantially to said frontface ofthe wafer. i V Y VReferences Cited bythe Examiner Y UNlTED STATES PATENTS 2,065,906 12/36' Pai-kerst al 339-252 x 2,157,051 v 5/39 Birdseye 339-146 2,592,130V 4/52 Erb e1 a1. V

2,701,273 2/55 Badeau 1 339-62 X 2,881,406y 4/59 Arson r 339-59 *A FOREIGN PATENTS 231,270 11/60 Australia.

1,161,384 3/58 France.

JosnrHD. sanas, Primary Examiner. 

1. AN ELECTRICAL CONNECTOR UNIT COMPRISING A BODY OF INSULATION MATERIAL HAVING A PLURALITY OF PASSAGES THERETHROUGH FROM A FRONT FACE TO A REAR FACE AND ADAPTED TO RECEIVE RESPECTIVE ELECTRICAL CONTACT MEMBERS THEREIN WHICH ARE INSERTABLE FROM THE REAR AND WHICH EACH HAVE AN ENLARGED SECTION DEFINING A REARWARDLY FACING SHOULDER AND A PLURALITY OF TRUNCATED, TUBULAR CONTACT RETENTION CONES INTEGRAL WITH SAID BODY AND COAXIAL WITH THE RESPECTIVE SAID PASSAGES, EACH OF SAID CONES TAPERING FOR WARDLY AND RADIALLY INWARDLY FROM THE WALL OF THE RESPECTIVE PASSAGE TO A FORWARD FREE END, EACH CONE BEING RESILIENTLY RADIALLY EXPANDABLE TO PERMIT SAID ENLARGED SECTION OF A RESPECTIVE CONTACT MEMBER TO PASS THERETHROUGH UPON FORWARD INSERTION OF THE CONTACT MEMBER INTO THE RESPECTIVE SAID PASSAGE, THE CONE CONTRACTING BEHIND THE SHOULDER ON THE CONTACT MEMBER TO LIMIT REARWARDLY MOVEMENT OF THE CONTACT MEMBER IN THE PASSAGE, AND EACH CONE BEING SUBSTANTIALLY RIGID IN AN AXIAL DIRECTION WHEN IN ITS CONTACTED POSITION SO AS TO PROVIDE A POSITIVE STOP AGAINST REARWARD MOVEMENT OF THE RESPECTIVE CONTACT MEMBER. 